Modular heated platform

ABSTRACT

A platform to be arranged adjacent to another platform to collectively form a heated walkway that minimizes the formation of ice on a surface of the walkway that is exposed to a sub-freezing environment. The platform includes an outermost surface to be exposed to the sub-freezing environment for providing traction for pedestrians walking on the platform, and a heating element for generating thermal energy to be transmitted to the outermost surface for minimizing the formation of ice on the outermost surface. A fastener is also provided for coupling the platform to a compatible feature of an adjacent platform to collectively form a walkway, and an electrical conductor delivers electric energy to the heating element and conducts electric energy from an external energy source to an adjacent platform.

FIELD OF THE INVENTION

The present invention relates to a heating device and use thereof. Moreparticularly, the present invention relates to a platform provided witha heated surface that minimizes ice formation on the platform. A walkwaycan be assembled from a plurality of interlocking modular platforms.

BACKGROUND OF THE INVENTION

Typically, external flooring surfaces such as sidewalks and stair treadsexposed to cold weather accumulate ice in on the exposed surface uponwhich people walk. This makes walking dangerous, and often requires theice to be removed at the expense of the property owner. The cost of iceremoval is particularly high for the owners of public facilities havingsignificant amounts of external flooring such as sidewalks, courtyards,external vending spaces, parking lots, and the like.

Of particular relevance to the present invention, sidewalks are commonlyencountered by pedestrians walking in icy conditions. Conventionalheated sidewalks typically include tubular passages embedded within theconcrete poured to initially create the sidewalk. Steam is transportedthrough the tubular passages to generate the thermal energy required toheat the exposed walking surface of the sidewalk. The thermal energyfrom the steam is conducted from within the concrete to the exposedwalking surface, thereby raising the temperature of the walking surfaceabove the freezing point of water.

The conventional steam-heated sidewalks, however, require a constantsupply of steam to minimize the formation of ice on the walking surfaceof the sidewalk. This is particularly true during prolonged periods ofcold weather. But since sidewalks are somewhat permanent structures,repairing and/or replacing the steam-heating system when a disruption ofsteam delivery occurs is time consuming, labor intensive and expensive.

Accordingly, there is a need in the art for heated flooring that canminimize the accumulation of ice on an external walking surface and thatovercomes the limitations of the prior art.

SUMMARY OF THE INVENTION

According to one aspect, the present invention provides a platform to bearranged adjacent to another platform to collectively form a heatedwalkway that minimizes the formation of ice on a surface of the walkwaythat is exposed to a sub-freezing environment. The platform includes atread with an outermost surface to be exposed to the sub-freezingenvironment for providing traction for pedestrians walking on theplatform, and a heating element for generating thermal energy to betransmitted to the tread for minimizing the formation of ice on theoutermost surface. A fastener can be used to couple the platform to acompatible feature of an adjacent platform to collectively form awalkway, and an electrical conductor for delivers electric energy to theheating element and from an external energy source to an adjacentplatform.

According to another aspect, the present invention provides a heatedwalkway for minimizing the formation of ice on a surface of the walkwayto be exposed to a sub-freezing environment and upon which pedestrianscan walk. The walkway includes a first platform and second a secondplatform. The first platform comprises a first heating element forgenerating thermal energy to be transmitted to the surface of thewalkway for minimizing the formation of ice on the surface, and afastener for coupling the first platform to the second platform tomaintain the position of the first platform relative to the secondplatform. The first platform also includes an electrical conductor fordelivering electric energy to the first heating element and conductingelectric energy between an external energy source and the secondplatform. The second platform includes a second heating element forgenerating thermal energy to be transmitted to the surface of thewalkway for minimizing the formation of ice on the surface, and a secondfastener that is compatible with the first fastener. Similar to thefirst platform, the second platform also includes an electricalconductor for delivering electric energy to the second heating elementand conducting electric energy between the first platform and a thirdplatform.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features and advantages of the present inventionwill become apparent to those skilled in the art to which the presentinvention relates upon reading the following description with referenceto the accompanying drawings, in which:

FIG. 1 is a top view of a platform in accordance with an embodiment ofthe present invention;

FIG. 2 is a bottom view of a platform in accordance with an embodimentof the present invention;

FIG. 3 is a top view of a walkway comprising a plurality of platforms inaccordance with an embodiment of the present invention;

FIG. 4 is a cross-sectional view of the platform shown in FIG. 1 takenalong line 4-4; and

FIG. 5 is a schematic illustration of a resistive heating element inaccordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Certain terminology is used herein for convenience only and is not to betaken as a limitation on the present invention, which is set forth inthe appended claims. Any relative language used herein, such as an“outermost surface,” is to be interpreted in view of the thoserelationships as shown in the drawings. Further, in the drawings,certain features may be shown in somewhat schematic form.

FIG. 1 is a top view of a heated platform 10 in accordance with anembodiment of the present invention. The platform 10 can be arrangedadjacent to one or more other platforms 10 to collectively form a heatedwalkway that minimizes the formation of ice on a surface of the walkwaythat is exposed to a sub-freezing environment, as described in detailbelow. The term “walkway” is used herein to refer to any surface uponwhich pedestrians can walk, such as sidewalks, stairs, ramps, parkinglots, driveways, and the like.

In general, the platform 10 includes a generally rectangular or squarebase 11 made from a rigid plastic that has favorable thermal properties.The favorable thermal properties include resistance to brittleness andbreakage over a wide range of temperatures, as well as suitableinsulation to minimize the loss of thermal energy generated by a heatingelement 22 (FIG. 4) to the ground supporting the platform 10. Althoughthe illustrative embodiments are described and illustrated in thedrawings as square, 4 ft×4 ft platforms, the present inventionencompasses all shapes in addition to square, including triangular,pentagonal, hexagonal, trapezoidal, and the like. All of these shapescan be interlocked into a lattice of platforms 10 to establish agenerally-uniform walkway without significant spaces between platforms10.

As shown in FIG. 1, the platform includes a tread 14 with an outermostsurface 18 (FIG. 4) that will be exposed to a sub-freezing environmentduring certain times of the year depending on the geographic location.The tread 14 can optionally be removable and replaceable, and canoptionally be provided with a texture or other traction-enhancingfeature on its outermost surface to provide pedestrians with tractionwhile they are walking on the platform. Examples of suitabletraction-enhancing features include grit, contours, and the like. This,in addition to the heat generated by the heating element 22 (FIGS. 4 and5) serve to minimize the likelihood that pedestrians will lose tractionand slip while walking on the platform 10.

Fasteners 26 a, 26 b extend outwardly from the sides of the platform 10for coupling the platform 10 to a compatible fastener 26 a, 26 b of anadjacent platform 10. Assembling the platforms 10 in this manner allowsfor the formation of a floor, sidewalk, ramp, stair, or other type ofsurface as desired. For the embodiment shown in the drawings,particularly FIGS. 1 and 4, it can be seen that the fastener 26 aincludes an inclined surface with a protruding rail 29 a and asimilarly-sized impression 32 a. Likewise, the compatible fastener 26 balso includes an inclined surface 27 b with a protruding rail 29 b and asimilarly-sized impression 32 a. The primary difference between thefasteners 26 a, 26 b is that the inclined surface 26 a is complementaryto the inclined surface 26 b. Thus, when two or more platforms 10 arepositioned adjacent to each other to form a walkway 36 or otherfloor-type surface as shown in FIG. 3, the inclined surface 27 a opposesthe inclined surface 27 b. Further, when the walkway is formed, theprotruding rail 27 a is disposed within the compatible impression 32 band the protruding rail 27 b is disposed within the compatibleimpression 32 a. Such features promote proper alignment of the pluralityof platforms 10 to allow for proper alignment of the conductors ofelectric energy, shown in FIG. 2. Locking pins (not shown) can beinserted through keyhole apertures 39 formed in the fasteners 26 a, 26 bin each platform 10, said keyhole apertures 39 being aligned when theplatforms 10 are assembled. The locking pins fix the relative positionof one platform 10 another platform 10 when aligned to form the walkway36.

A heating element 22, such as that shown in FIG. 5 for example, isprovided to the platform 10 to generate thermal energy for minimizingthe formation of ice on the platform in a sub-freezing environment. Thethermal energy generated by the heating element 22 is transmitted byconduction, convection, radiation, any other mechanism or combinationthereof to the outermost surface 18 of the tread. Due to the supply ofthermal energy by the heating element, the outermost surface 18 of thetread is maintained at a temperature above the freezing temperature ofwater, which is approximately 0° C., or 32° F. at sea level.

The heating element 22 shown in FIG. 5 is an electronic resistiveheating element, but the present invention encompasses anyheat-generating device that can convert electric energy into thermalenergy. The resistive heating element 22 includes an array of metallicconductors 42 supported by a flexible, dielectric substrate 45. Electricenergy is supplied to and from the array of conductors 42 by leads 48that conduct electric energy transported by the power-supply lines 52(FIG. 2) of the platform 10. Due to the resistance of the conductors 42,at least a portion of the electric energy delivered to the conductors 42is converted into the thermal energy that is eventually transmitted tothe outermost surface 18 of the tread 14.

A flexible heating element 22 such as that shown in FIG. 5 allows forlocation of the heating element at a variety of locations throughout theplatform 10. The embodiment shown in FIG. 4 discloses one suitablelocation for the heating element 22 relative to the other features ofthe platform 10. In FIG. 4, the heating element 22 is disposed betweenthe tread 14 and the base 11 of the platform 10. This offers at leasttwo advantages to other locations within or on the platform 10. First,the tread 14 provides a degree of protection to the heating element 22from the sub-freezing environment as well as the forces imparted on theplatform 10 by pedestrians as they walk on the platform 10. And second,the base 11 provides thermal insulation between the heating element 22and the ground supporting the platform 10. Although suitable thermalinsulation can be provided by the base 11 with the heating-element in avariety of locations, one embodiment of the present invention providesfor a ratio of: ${\frac{\begin{matrix}{{{Overall}\quad{Heat}\quad{Transfer}\quad{Coefficient}}\quad} \\{{{of}\quad{the}\quad{Thermall}\quad{PathFrom}\quad{the}\quad{Heating}}\quad} \\{{Elementto}\quad{the}\quad{Outermost}\quad{Surface}}\end{matrix}}{\begin{matrix}{{{Overall}\quad{Heat}\quad{Transfer}\quad{Coefficient}\quad{of}\quad{the}}\quad} \\{{{Thermal}{\quad\quad}{Path}\quad{from}\quad{the}\quad{Heating}\quad{Element}\quad{to}}\quad} \\{{the}\quad{Surface}\quad{Supporting}\quad{the}\quad{Platform}}\end{matrix}} \times 100\%} \leq {20\%}$

Other embodiments include a heating element 22 supported on theoutermost surface 18 of the tread 14, integrating the heating element 22within the tread 14, and integrating the heating element 22 directlyinto the material used to create the base 11 of the platform 10. Forembodiments expose the heating element 22 to the ambient environment,the term “outermost surface” refers to the outermost surface of theheating element, and not the outermost surface of the tread 14. In anyevent, the outermost surface 18 is used herein to refer to the surfaceof the platform 10 that will be exposed to the sub-freezing environmentand upon which ice formation can occur.

Electric contacts 56 also extend through the fasteners 26 a, 26 b tofacilitate the conduction of electric energy from one platform 10 toanother when the to platforms 10 are coupled together to form thewalkway 36. Each contact 56 is made from a conductor of electricity,such as a metal, and conducts electric energy from an external powersource and/or another platform 10 to the power-supply lines 52, shown inFIG. 2. Each contact can optionally include a quick-disconnect plugallowing for rapid connection or disconnection of the contacts to anexternal source of electric energy or another platform 10.

The location of the contacts 56 are uniform such that when the fasteners26 a, 26 b overlap when the platforms 10 for a walkway 36, the contact56 in a fastener 26 a of a first platform 10 is in contact with acontact 56 in a fastener 26 b of a second platform 10. Thus, when theplatforms 10 are assembled to form a walkway 36, the electric energysupplied by a common external energy source can be conducted to allplatforms 10 in the walkway 36 without the need for a dedicated wiringsystem aside from that provided to each platform 10. Accordingly, thepower-supply lines 52 are electrical conductors that deliver electricenergy to the heating element 22 and conduct electric energy from anexternal energy source to an adjacent platform 10.

To somewhat automate control of the heating-element provided to aplatform 10, a temperature sensor and thermostat (not shown) canoptionally be provided to the platform 10. The temperature sensor can bedisposed anywhere within or on the platform 10, and even remotely fromthe platform 10 from where it can sense a temperature indicative ofwhether ice is likely to form on the outermost surface 18 of the tread14, where the ambient temperature can be below the freezing temperatureof water. For instance, the temperature sensor can be concealed beneaththe outermost surface 18 of the tread 14, between the tread 14 and theheating element 22, or anywhere else on the platform 10. Regardless ofwhere the temperature sensor is installed, the temperature measure bythe temperature sensor is to be correlated to the temperature of theoutermost surface 18. Other embodiments include the use of an infraredtemperature sensor.

Operation of a thermostat can automatically respond to changes in thetemperature of the outermost surface 18 (either calculated base on anindirect temperature measurement by the temperature sensor or measureddirectly by the temperature sensor) to activate, deactivate, and prolongor shorten the duration of operation of the heating element 22 asappropriate. If, for example, significant ice accumulation is suspecteddue to a prolonged period of sub-freezing ambient temperatures, thethermostat can activate and ensure a sufficient duration of activationof the heating element 22 to heat the outermost surface 18.

A temperature sensor can be provided to each platform 10 making up awalkway 36, a group of platforms forming a region of a walkway 36, anentire walkway, or any other arrangement. Likewise, a thermostat can beassigned the task of controlling operation of the heating element 22 ofeach single platform 10 in a walkway 36, a plurality of platforms 10 ina walkway 36, or the entire walkway 36. Thus, each platform 10 in awalkway 36 can be individually controlled, controlled as part of aregion of platforms 10, or controlled as the entire walkway 36.

From the above description of the invention, those skilled in the artwill perceive improvements, changes and modifications. Suchimprovements, changes and modifications within the skill of the art areintended to be covered by the appended claims.

1. A platform to be arranged adjacent to another platform tocollectively form a heated walkway that minimizes the formation of iceon a surface of the walkway that is exposed to a sub-freezingenvironment, the platform comprising: an outermost surface to be exposedto the sub-freezing environment for providing traction for pedestrianswalking on the platform; a heating element for generating thermal energyto be transmitted to the outermost surface for minimizing the formationof ice on the outermost surface; a fastener for coupling the platform toa compatible feature of an adjacent platform to collectively form awalkway; and an electrical conductor for delivering electric energy tothe heating element and conducting electric energy from an externalenergy source to an adjacent platform.
 2. The platform according toclaim 1 further comprising a temperature sensor for sensing atemperature indicative of whether ice is likely to form on the surfaceof the tread that is to be exposed to the sub-freezing environment. 3.The platform according to claim 2, wherein the temperature sensed by thetemperature sensor is a temperature of the surface of the tread that isto be exposed to the sub-freezing environment.
 4. The platform accordingto claim 2 further comprising a thermostat for controlling operation ofthe heating element as a function of the temperature sensed by thetemperature sensor.
 5. The platform according to claim 1, wherein theheating element is integrated within the tread.
 6. The platformaccording to claim 1, wherein the heating element is an electric,resistive heating element.
 7. The platform according to claim 1 furthercomprising a connector that cooperates with a compatible connectorprovided to an external energy source upon placement of the platformadjacent to the external energy source.
 8. The platform according toclaim 1, wherein the heating element and electrical conductor areintegrated within the platform, thereby forming a modular platform thatcan be replaced as a unit.
 9. The platform according to claim 1, whereinthe platform is formed into at least one of a sidewalk, a ramp, and astair.
 10. A heated walkway for minimizing the formation of ice on asurface of the walkway to be exposed to a sub-freezing environment andupon which pedestrians can walk, the walkway comprising a first platformand second a second platform, wherein the first platform comprises: afirst heating element for generating thermal energy to be transmitted tothe surface of the walkway for minimizing the formation of ice on thesurface; a fastener for coupling the first platform to the secondplatform to maintain the position of the first platform relative to thesecond platform; and an electrical conductor for delivering electricenergy to the first heating element and conducting electric energybetween an external energy source and the second platform; and whereinthe second platform comprises: a second heating element for generatingthermal energy to be transmitted to the surface of the walkway forminimizing the formation of ice on the surface; a second fastener thatis compatible with the first fastener; and an electrical conductor fordelivering electric energy to the second heating element and conductingelectric energy between the first platform and a third platform.
 11. Thewalkway according to claim 10, wherein the first and second platformseach further comprise electrical contacts that engage each other uponpositioning the first platform adjacent to the second platform toconduct electric energy between the first and second platforms.
 12. Thewalkway according to claim 10, wherein at least one of the firstplatform and the second platform further comprises a temperature sensorfor sensing a temperature indicative of whether ice is likely to form onthe surface of the walkway that is to be exposed to the sub-freezingenvironment.